Various search methods have been proposed for searching a database holding a number of image data for a desired image. These search methods are briefly classified into the following two methods.    (1) Making a search based on non-image information such as a keyword or image sensing date linked to an image    (2) Making a search based on a feature amount (luminance/chrominance information, an image frequency, a histogram and the like) of image itself
In the latter method which is called a “similar image search”, an image is presented to the database, and an image search is performed with the feature amount of the image as a search key. This method provides an intuitive and simple search interface to a user who does not have special image processing knowledge.
It is ineffective that plural users independently have a huge image database. Accordingly, various client/server type image databases have been proposed and practically used in centralized management of image data. However, upon transmission of image as a search result from a server to a client, since it takes time for the client to display the image due to a network band, the image search cannot be always performed efficiently.